aarch64: Support GOT Relative relocations in PIC mode (#5550)

* cranelift: Add `adrp` encoding to AArch64 backend

* cranelift: Support GOT Symbol References in AArch64

* cranelift: Add MachO GOT relocations

* cranelift: Do not mark the GOT PageOffset12 MachO relocation as relative

cranelift/codegen/src/isa/aarch64/inst.isle

@@ -852,6 +852,11 @@
         (rd WritableReg)
         ;; Offset in range -2^20 .. 2^20.
         (off i32))
+      
+       ;; Compute the address (using a PC-relative offset) of a 4KB page.
+       (Adrp
+        (rd WritableReg)
+        (off i32))
 
        ;; Raw 32-bit word, used for inline constants and jump-table entries.
        (Word4